Solar system – electricity and heat from solar energy

Just one hour of sunshine is enough to cover humanity's annual energy needs in their entirety. With a solar system from Viessmann, this free and inexhaustible source of energy can also be used in your own home.

While the solar thermal collectors convert the incoming radiation into heat, solar photovoltaic modules generate electricity. But how does a solar system work? What distinguishes photovoltaics and solar thermal energy and how can both be integrated into the home in the best way possible?

Solar thermal converts radiant energy into heat

A solar thermal system from Viessmann uses the free radiation from the sun to generate heat for DHW and heating. This requires the use of solar collectors, a solar cylinder and a network of pipes that connects all the components together.

The solar collectors of a solar thermal system have the most important task in its functioning, as they absorb the sun's radiation, convert it into thermal energy and transfer this to the solar medium. There is a choice of flat-plate collectors such as the Vitosol 200-FM or vacuum tube collectors such as the Vitosol 200-TM. The vacuum tube collectors ensure maximum yields on the smallest of surfaces.

Depending on the type of solar thermal system, a pump then conveys the heated solar medium through a heat exchanger in a DHW cylinder or heating water buffer cylinder. DHW cylinders such as the Vitocell 100-B/-W from Viessmann are used when the function of solar thermal is intended to provide domestic hot water heating. If the system is also intended to support heating, it can be combined with the Vitocell 360-M, for example – the multi mode heating water buffer cylinder with integral connection to the collectors. Both absorb the thermal energy from the solar system and store it until hot water or space heating is needed. Optimally matched complete solutions such as the Viessmann Vitosol 141-FM DHW solar package ensure maximum efficiency.

Photovoltaics generate electricity from solar radiation

The function of a photovoltaic system differs from that of a solar thermal system. This is because photovoltaics convert solar radiation into electrical energy. To this end, and in addition to solar panels or solar modules, the system incorporates an inverter and an optional power storage unit.

Solar panels, such as the Vitovolt 300 of a Viessmann solar PV system, are made up of numerous solar cells. These use the photo effect to convert radiation energy into direct current. An inverter then generates alternating current. This is necessary for the electrical energy to be used in the home or to export it to the public grid. While solar systems used to be designed more for the latter, self-consumption is more lucrative today than it once was. This is because homeowners have to purchase less electricity from the public grid and can thus save more on energy costs. Nevertheless, electricity is almost always needed at times when the solar PV system is not supplying any, such as in the evening and overnight. With a power storage unit such as the Viessmann Vitocharge, this shift can be cancelled out. With a battery system in place, the solar power generated during the day is also available at night. This helps to makes you self-reliant and significantly reduces your electricity costs.

For whom is the Viessmann solar system worthwhile?

The use of photovoltaics and solar thermal is always beneficial when the solar collectors and solar modules on the roof can harvest plenty of energy. This requires:

• Sufficient space for collectors and solar panels
• A south facing roof for the solar system
• A roof surface with an inclination of 30 to 40 degrees
• Trees, houses or mountains that do not cast a shadow on the house

Even if a roof does not meet all the requirements, a Viessmann solar system can still be beneficial. It is possible to incline collectors and solar modules at the optimal angle with a scaffolding system. If the roof surface faces east or west, the collector and module surfaces should be larger. Otherwise, the yields will be considerably lower than with a southerly orientation.

Increase economic efficiency through self-consumption

A Viessmann power storage unit increases the self-consumption of self-generated electricity and thus the efficiency of the photovoltaic system. The system will charge the power storage unit when your home is not calling for electricity. This power is used as required, for example to run electrical appliances. If the power storage unit is fully charged and no consumers are connected, excess power will be exported to the grid and remunerated accordingly.